Added thermal conductivity

src/include/units/physical/dimensions.h

@@ -149,6 +149,9 @@ struct dim_heat_capacity : derived_dimension<Child, U, exp<E, 1>, exp<T, -1>> {}
 template<typename Child, Unit U, DimensionOf<dim_heat_capacity> C, DimensionOf<dim_mass> M>
 struct dim_specific_heat_capacity : derived_dimension<Child, U, exp<C, 1>, exp<M, -1>> {};
 
+template<typename Child, Unit U, DimensionOf<dim_power> P, DimensionOf<dim_length> L, DimensionOf<dim_thermodynamic_temperature> T>
+struct dim_thermal_conductivity : derived_dimension<Child, U, exp<P, 1>, exp<L, -1>, exp<T, -1>> {};
+
 }  // namespace physical
 
 template<typename T>
@@ -253,4 +256,7 @@ concept HeatCapacity = physical::QuantityOf<T, physical::dim_heat_capacity>;
 template<typename T>
 concept SpecificHeatCapacity = physical::QuantityOf<T, physical::dim_specific_heat_capacity>;
 
+template<typename T>
+concept ThermalConductivity = physical::QuantityOf<T, physical::dim_thermal_conductivity>;
+
 }  // namespace units

src/include/units/physical/si.h

@@ -43,6 +43,7 @@
 #include "si/pressure.h"
 #include "si/resistance.h"
 #include "si/surface_tension.h"
+#include "si/thermal_conductivity.h"
 #include "si/velocity.h"
 #include "si/voltage.h"
 #include "si/volume.h"

src/include/units/physical/si/thermal_conductivity.h

@@ -0,0 +1,47 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/physical/dimensions.h>
+#include <units/physical/si/power.h>
+#include <units/physical/si/temperature.h>
+#include <units/quantity.h>
+
+namespace units::si {
+
+struct watt_per_metre_kelvin : unit<watt_per_metre_kelvin> {};
+
+struct dim_thermal_conductivity : physical::dim_thermal_conductivity<dim_thermal_conductivity, watt_per_metre_kelvin, dim_power, dim_length, dim_thermodynamic_temperature> {};
+
+template<Unit U, Scalar Rep = double>
+using thermal_conductivity = quantity<dim_thermal_conductivity, U, Rep>;
+
+inline namespace literals {
+
+// J/K
+constexpr auto operator"" q_W_per_m_K(unsigned long long l) { return thermal_conductivity<watt_per_metre_kelvin, std::int64_t>(l); }
+constexpr auto operator"" q_W_per_m_K(long double l) { return thermal_conductivity<watt_per_metre_kelvin, long double>(l); }
+
+}  // namespace literals
+
+}  // namespace units::si